I have a directory /home/user/MyDocs/.sounds/Music that contains all my music (encoded in AAC+).
I have organized my music in a folder structure artist/album/ and (according to mp3tag) all my tags are correct.
When I build the tracker database (using trackercfg) I only see around 40% of my songs, there are just over 5000 tracks and media player tells me there are just over 2000.
If I look at the trackerd log, there are loads and loads of entries that say:

Tracker-Critical **: Could not open directory 'file:///home/user/MyDocs/.sounds/Music/artist/album': Too many open files

Where artist and album are part of my collection. What does this actually mean and how do I get round it so that media player sees all my tracks?

I don't have my N900 in front of me right now to try this for you, but when I have this problem on my desktop, I try this as root in the xterm:

(view file max set in proc)
cat /proc/sys/fs/file-max
1048576

(view file max set in Pam.d, but I don't think maemo uses pam.d...)
cat /etc/security/limits.conf
* soft nofile 1048576
* hard nofile 1048576

(view file max in sysctl)
sudo cat /etc/sysctl.conf
fs.file-max=1048576

If you find that the N900 has any of the above files and you change them, reboot to make the change active. Then after reboot, run the following command to view the current file max:

ulimit -n
1048576